The approval process for medical devices has been the topic of growing scrutiny. Today, a study published in the Archives of Internal Medicine suggests most medical devices recalled for life-threatening or very serious hazards were cleared by the Food and Drug Administration through an expedited review process called 510(k), or were considered so "low risk" they were exempt from review entirely.

Marketing campaigns on TV and online hype the "new and improved products" directly to patients.

"Since patients are exposed to new products through direct-to-patient marketing, they assume these products have been time-tested and well-established," said Dr. Andrew Pearle, an orthopedic surgeon at Hospital for Special Surgery in New York City. "But often there is little clinical data to support the marketing claims."